Furthermore, the role of IL-8 in PDT differs from radiotherapy, in which IL-8 induces an epithelial–mesenchymal transition [38] and tumor cell repopulation after radiotherapy via RIP1/RIP3/MLKL/JNK/IL-8 pathways [35], leading to a poor prognosis for cancer patients. Here, CXCL8 is linked to cancer.